In the Feb. 16 SN: Robots roll into the classroom, brain zaps for severe depression, particle colliders of the future, how to walk like a tetrapod, sleepless nights boost Alzheimer's proteins and more.

It probably comes as no surprise that the New Horizons mission to Pluto takes the top spot in Science News’ list of 2015’s most important stories.

Since New Horizons awoke last December, we’ve devoted more than two dozen stories in the magazine and on the website — upwards of 10,000 words — to this first-ever visit. No other science news this year garnered so many headlines.

Mountains of water ice tower thousands of meters over fields of frozen nitrogen and methane. Glaciers etched with channels hint at heat bubbling up from below. A patchwork of new and old terrains — some laid down in the last 10 million years, some as old as the planet itself — blanket the ground. And what appear to be two ice volcanoes punch through the terrain.

A revolutionary gene-editing technology made headlines this year as much for the ethical and societal issues it raised as for the scientific accomplishments it enabled.

CRISPR (pronounced crisper) burst on the scientific scene in 2012, when researchers transformed what had originally been identified as a rudimentary immune system in bacteria into one of the most powerful tools in...

Scientists trying to untangle the human evolutionary family’s ancient secrets welcomed a new set of tantalizing and controversial finds this year. A series of fossil discoveries offered potentially important insights into the origins of the human genus, Homo. Most notably, a group of South African fossils triggered widespread excitement accompanied by head-scratching and vigorous debate...

Age was all the rage this year, as headlines about a provocative study blared what many people already suspected: People grow old at vastly different rates.

The study, out of Duke University, analyzed the health of nearly one thousand 38-year-olds and found that some resembled people a decade older while others appeared years younger (SN: 8/8/15, p. 10). Researchers determined this...

A supposed pause in global warming that has been fodder for climate change doubters never really existed, researchers reported in 2015.

The fuss began when studies showed that decades of warming appeared to have leveled off in 1998. From that year through 2012, Earth’s yearly average surface temperature increased at one-third to one-half the average rate from 1951 through 2012. This...

Experimental results that don’t hold up to replication have caused consternation among scientists for years, especially in the life and social sciences (SN: 1/24/15, p. 20). In 2015 several research groups examining the issue reported on the magnitude of the irreproducibility problem. The news was not good.

Results from only 35 of 97 psychology experiments published in three major...

As it winds up its studies of Saturn’s moon Enceladus, NASA’s Cassini spacecraft is offering the best evidence yet that this moon’s buried ocean could be a great place to search for extraterrestrial life.

Cassini, which has orbited Saturn since 2004, has swooped past Enceladus more than 20 times. But only recently have measurements confirmed that, beneath the moon’s icy shell, an...

Microbes discovered in Arctic mud could be the closest relatives yet found to the single-celled ancestor that swallowed a bacterium and made life so complicated. Biologists have proposed that this swallowing event, perhaps 1.8 billion years ago, led to complex cells with membrane-wrapped organelles, the hallmark of all eukaryotes from amoebas to zebras.

Some pesky loopholes no longer plague a crucial test for assessing the weirdness of quantum mechanics. Experiments reported in 2015 definitively demonstrate that the quantum world violates locality, the principle that events sufficiently separated in spacetime must be independent. “It’s a landmark result,” says Matthew Leifer, a quantum physicist at the Perimeter Institute for Theoretical...